JP2017018917A - Method and device for performing adsorption separation of ch4 from biogas - Google Patents
Method and device for performing adsorption separation of ch4 from biogas Download PDFInfo
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Abstract
Description
本発明は水分、揮発性有機化合物（ＶＯＣ）、二酸化炭素（ＣＯ２）、硫化水素（Ｈ２Ｓ）、有機硫黄、有機ケイ素等を含有するメタン発酵槽からのＣＨ４含有湿りバイオガスからのコンパクトで高効率なＣＨ４の分離方法及び装置、特に吸着工程で塔後方に残留したＣＨ４を補助吸着塔に吸着貯蔵し、次の吸着工程の昇圧工程の昇圧気体として供給して、ＣＨ４分離・回収効率を向上させたバイオガスからのＣＨ４の分離方法及び装置に関する。 The present invention is derived from a CH 4 -containing wet biogas from a methane fermenter containing moisture, volatile organic compounds (VOC), carbon dioxide (CO 2 ), hydrogen sulfide (H 2 S), organic sulfur, organosilicon, etc. compact and high efficiency CH 4 separation method and apparatus, in particular a CH 4 remaining in the column behind the adsorption step is adsorbed and stored in the auxiliary adsorption tower, and supplied as a boost gas boosting step for the next adsorption step, CH 4 The present invention relates to a method and apparatus for separating CH 4 from biogas with improved separation / recovery efficiency.
バイオガスとは、下水汚泥、食品廃棄物、畜産排泄物などのバイオマスをメタン発酵させることにより得られるカーボンニュートラルなエネルギー源の一つである。バイオガスは、一般に、メタンを概ね５０〜６５％、二酸化炭素を概ね３０〜４０％含み、硫化水素、シロキサン類、メチルメルカブタン、飽和水分等の成分を微量に含むものである。当該バイオガス中のメタンを燃料として利用するためには、バイオガスから二酸化炭素を除去する必要があり、さらに有害成分である硫化水素、シロキサン類は特に除去する必要がある。現在最もよく使用されているＣＯ２選択型吸着剤を使用したＣＨ４分離・精製装置としては、ＰＳＡ−ＣＨ４タイプの装置が知られている。 Biogas is one of carbon neutral energy sources obtained by methane fermentation of biomass such as sewage sludge, food waste, and livestock excrement. Biogas generally contains about 50 to 65% of methane and about 30 to 40% of carbon dioxide, and contains trace amounts of components such as hydrogen sulfide, siloxanes, methyl mercaptan, and saturated water. In order to use methane in the biogas as a fuel, it is necessary to remove carbon dioxide from the biogas, and it is also necessary to remove particularly harmful hydrogen sulfide and siloxanes. The CH 4 separation and purification apparatus using a CO 2 selective adsorbent that is currently most commonly used, PSA-CH4 types of devices are known.
Ｌｉｎｄｅ社（現ＵＯＰ社モレキューラーシブス．デイビジョン）により工業的な製造の開始された合成ゼオライトは、ＣＨ４−ＣＯ２の２成分系において大きなＣＯ２吸着量とＣＯ２選択性を有することが示されている。ここで１００〜２００ｋＰａ−ａｂｓの大気圧以上の高圧にバイオガスを圧縮し、Ｌｉ−ＬＳＸ型ゼオライト（低ＳｉＯ２／Ａｌ２Ｏ３比Ｘ型ゼオライト）をＣＯ２選択型吸着剤として充填されたＣＯ２吸着塔に導いてバイオガスの中の３０％を占めるＣＯ２を吸着して塔頂から９５ｖｏｌ％程度のＣＨ４を取り出す吸着工程と、吸着ＣＯ２で飽和したＣＯ２吸着塔を大気圧または大気圧以下の真空に近い状態に導いた後、塔頂から製品ＣＨ４の一部を流してＣＯ２選択型吸着剤を再生する工程（向流パージ）から構成される、すなわち、高圧吸着と大気圧再生または真空再生から成る２搭式のＣＨ４製造装置が標準的な装置として既知である。 Linde (now UOP Inc. leak queue error inclusive scan. Day Vision) by industrial preparation of the starting synthetic zeolites have a larger CO 2 adsorption amount and CO 2 selectivity in 2-component systems of CH 4 -CO 2 It is shown. Here, the biogas was compressed to a pressure higher than the atmospheric pressure of 100 to 200 kPa-abs, and Li-LSX type zeolite (low SiO 2 / Al 2 O 3 ratio X type zeolite) was packed as a CO 2 selective adsorbent. and the adsorption step of taking out the CH 4 of about 95 vol% from the column top by adsorbing CO 2 occupying 30% in the biogas is guided to CO2 adsorption tower, the CO 2 adsorption column saturated with adsorbed CO 2 atmospheric pressure or It is composed of a process (countercurrent purge) for regenerating the CO 2 selective adsorbent by introducing a part of the product CH 4 from the top of the tower after being brought to a state close to a vacuum of atmospheric pressure or lower, that is, high-pressure adsorption and A two-column CH 4 production device consisting of atmospheric pressure regeneration or vacuum regeneration is known as a standard device.
当該装置は、２，０００ｍ３Ｎ／ｈ以下の中小容量でのメタン精製・分離回収製造が可能なことから、操作、保守が容易で、かつコンパクトであり、メタン発酵槽で放出されるバイオガスの精製・分離回収を中心に普及している。ＰＳＡ−ＣＨ４の電力原単位（１ｍ３ＮのＣＨ４の精製・分離回収に必要な消費電力）の低減を目的として、３００〜５００ｋＰａ−ａｂｓの比較的低圧に吸着圧力を低減し、かつ５０ｋＰａ−ａｂｓ程度の減圧再生を行う加圧吸着−減圧再生が採用される場合もある。さらに、一段の電力原単位の低減のために、大気圧近傍で吸着を行い、再生は１０〜３０ｋＰａ−ａｂｓのかなりの真空で行われる大気圧吸着−減圧再生も採用されており、これらの操作条件は、初期に開発された高圧吸着−大気圧再生よりも電力原単位低減に優れている。これらの装置および工程に使用される吸着剤としては、当初Ｃａイオン交換Ａ型ゼオライトが主として使用されたが、サイクルタイムの短縮による装置コンパクト化を意図して、吸着速度の大きな吸着剤が必要なことから、Ｎａイオン交換、Ｌｉイオン交換Ｘ型ゼオライトが採用されるようになっている。 The device is capable of methane purification / separation / recovery / manufacturing in a small and medium capacity of 2,000 m 3 N / h or less, so it is easy to operate and maintain, is compact, and is biogas released in the methane fermenter. It is widely used mainly for refining, separation and recovery. In order to reduce the power consumption of PSA-CH 4 (power consumption necessary for purification / separation and recovery of 1 m 3 N CH 4 ), the adsorption pressure is reduced to a relatively low pressure of 300 to 500 kPa-abs and 50 kPa. In some cases, a pressure adsorption-reduced pressure regeneration that performs a reduced pressure regeneration of about -abs is employed. Furthermore, in order to reduce the unit of power consumption in one stage, adsorption is performed near atmospheric pressure, and regeneration is performed using atmospheric pressure adsorption-regeneration under reduced pressure of 10 to 30 kPa-abs. The conditions are superior to the reduction in power consumption rate than the high-pressure adsorption-atmospheric pressure regeneration developed in the early stage. As the adsorbent used in these apparatuses and processes, Ca ion-exchanged A-type zeolite was mainly used at first, but an adsorbent with a high adsorption rate is required for the purpose of downsizing the apparatus by shortening the cycle time. For this reason, Na ion exchange and Li ion exchange X-type zeolite have been adopted.
しかしながら、これらの装置および方法においては、５００ｍ３Ｎ／ｈ以下のＣＨ４精製・分離回収では、電力原単位の低減は図れるものの、設備投資を考慮すると、ＣＨ４製造のトータルコストの低減はそれ程有効でなかった。例えば、中容量のＣＨ４製造装置として１５ｍ３Ｎ／ｈのＣＨ４精製・分離回収装置を例示すると、高圧吸着−大気圧再生のＰＳＡ−ＣＨ４の設備費が５００万円程度、電力原単位が１ｋＷｈ／ｍ３Ｎ−ＣＨ４であるので、これを大気圧吸着−真空再生に変更しても、設備費１，２００万円程度、電力原単位が０．５ｋＷｈ／ｍ３Ｎ−ＣＨ４となり、電力量単価を１０円／ｋＷｈとすると１年間の電力コスト低減は、１２０万円／年から６０万円／年と６０万円／年のコストダウンにとどまり、７００万円の設備費増を吸収できなかった。したがって、大容量メタン精製・分離回収製造による電力原単位の低減によるコストの低減は、未だ十分ではない。 However, in these apparatuses and methods, the reduction in the basic unit of electric power can be reduced by CH 4 purification / separation recovery of 500 m 3 N / h or less, but considering the capital investment, the total cost reduction of CH 4 production is much lower. It was not effective. For example, a 15 m 3 N / h CH 4 purification / separation / recovery device is illustrated as a medium-capacity CH 4 production device. Since it is 1 kWh / m 3 N-CH 4 , even if this is changed to atmospheric pressure adsorption-vacuum regeneration, the facility cost is about 12 million yen, and the power consumption is 0.5 kWh / m 3 N-CH 4 If the unit price of electricity is 10 yen / kWh, the reduction in power cost for one year will be reduced from 1.2 million yen / year to 600,000 yen / year and 600,000 yen / year, resulting in an increase in equipment costs of 7 million yen Could not be absorbed. Therefore, the cost reduction due to the reduction of the power consumption rate by the large-capacity methane purification / separation recovery production is not yet sufficient.
本発明はこのような従来技術における問題点を解決し、従来のメタン精製・分離製造法よりもさらに安価で電力原単位も低値を維持する低コストの、バイオガスからＣＨ４を吸着分離するための方法及びそのための装置を提供することを目的とする。 The present invention solves such problems in the prior art, and adsorbs and separates CH 4 from biogas, which is cheaper than conventional methane refining / separation production methods and low in cost, maintaining a low power intensity. It is an object to provide a method and an apparatus therefor.
本発明は、ＣＯ２吸着工程、残留ＣＨ４回収工程、減圧再生工程、残留ＣＨ４回収工程、昇圧工程を含み、これらを繰り返すバイオガスからＣＨ４を分離する方法であって、
前方からＨ２Ｓ・有機硫黄選択型吸着剤、水分選択型吸着剤、揮発性有機化合物（以下、ＶＯＣと示す）・有機ケイ素選択型吸着材の順序で吸着剤を充填され、さらに後方にＣＯ２選択型吸着剤を充填されたＣＯ２吸着塔に、圧力調整装置により大気圧より高い圧力としＣＨ４を主成分とする湿りバイオガスを供給して、ＶＯＣ、ＣＯ２、Ｈ２Ｓ、有機硫黄、有機ケイ素、水分を除去して塔後方からＣＨ４を回収して（ＣＯ２吸着工程）、
ＣＨ４濃度が低下する前に、塔後方に設置した補助吸着塔の前方とＣＯ２吸着塔の後方を連結して、塔後方に残留するＣＨ４を補助吸着塔に移行し（残留ＣＨ４回収工程１）、
補助吸着塔の前方とＣＯ２吸着塔の後方の連結を閉じ、真空ポンプ／ブロワー兼用回転機械で大気圧未満の圧力でＣＯ２吸着塔の塔前方から吸着したＶＯＣ、ＣＯ２、Ｈ２Ｓ、有機硫黄、有機ケイ素、水分を系外に排気した後（減圧再生工程）、
再度、補助吸着塔の前方とＣＯ２吸着塔の後方を連結して、大気圧のＣＯ２吸着塔の後方と補助吸着塔の前方を連結して回収したＣＨ４をＣＯ２吸着塔の後方へ移動させ、（残留ＣＨ４回収工程２）、
その後、ＣＨ４吸着塔の圧力を上昇させ（昇圧工程）、
ＣＨ４含有湿りバイオガスを供給するＣＯ２吸着工程に戻ることを特長とする、バイオガスからＣＨ４を分離する方法に関する。さらに、本発明のバイオガスからＣＨ４を分離するための装置に関する。
The present invention includes a CO 2 adsorption step, a residual CH 4 recovery step, a decompression regeneration step, a residual CH 4 recovery step, a pressure increase step, and a method for separating CH 4 from biogas that repeats these steps,
The adsorbent is filled in the order of H 2 S / organic sulfur selective adsorbent, moisture selective adsorbent, volatile organic compound (hereinafter referred to as VOC) / organic silicon selective adsorbent from the front, and CO in the rear. A wet biogas having a pressure higher than atmospheric pressure and a main component of CH 4 is supplied to a CO 2 adsorption tower packed with a two- selective adsorbent by using a pressure regulator, and VOC, CO 2 , H 2 S, organic Sulfur, organosilicon, moisture are removed and CH 4 is recovered from the rear of the tower (CO 2 adsorption step),
Before the CH 4 concentration decreases, the front of the auxiliary adsorption tower installed behind the tower is connected to the rear of the CO 2 adsorption tower, and CH 4 remaining behind the tower is transferred to the auxiliary adsorption tower (residual CH 4 recovery). Step 1),
Close coupling of the rear of the front and CO 2 adsorption tower of the auxiliary adsorption tower, VOC adsorbed from the tower in front of CO 2 adsorption column at a pressure less than atmospheric pressure by a vacuum pump / blower combined rotary machine, CO 2, H 2 S, After exhausting organic sulfur, organic silicon, and moisture out of the system (reduced pressure regeneration process),
Again, by connecting the rear of the front and CO 2 adsorption tower of the auxiliary adsorption tower, CH 4 and CO 2 to the rear of the adsorption tower were collected by connecting the front of the rear auxiliary adsorption tower of the CO 2 adsorption column at atmospheric pressure (Residual CH 4 recovery step 2),
Thereafter, the pressure of the CH 4 adsorption tower is increased (pressure increase step),
The present invention relates to a method for separating CH 4 from biogas, which is characterized by returning to a CO 2 adsorption step for supplying CH 4 -containing wet biogas. Furthermore, it relates to an apparatus for separating CH 4 from the biogas of the present invention.
上述の従来技術である１５ｍ３Ｎ／ｈのＣＨ４精製・分離回収製造装置のコストについては、高圧吸着−大気圧再生のＰＳＡ−ＣＨ４が、バイオガス圧縮機、ＣＯ２吸着塔２塔、バルブ８個を基本構造として設備費が７００万円程度、電力原単位が１ｋＷｈ／ｍ３Ｎ−Ｏ２、１年間の消費電力が、電力量単価を１０円／ｋＷｈとすると１年間の電力コストが、１２０万円／年である。それに対して、本発明のバイオガスからＣＨ４を分離する方法およびバイオガスからＣＨ４を分離するための装置であれば、高圧吸着−大気圧再生のＰＳＡ−ＣＨ４が、ブロワー／真空ポンプ兼用回転機械、ＣＯ２吸着塔５塔、補助吸着塔バルブ４個を基本構造として設備費が４００万円程度に削減され、補助吸着塔による残留ＣＨ４の回収と昇圧工程への供給で、ＣＨ４回収率が従来の８０％から９０％程度に増大するため、電力原単位が０．５ｋＷｈ／ｍ３Ｎ−ＣＨ４に低減され、１年間の消費電力が、電力量単価を１０円／ｋＷｈとすると１年間の電力コストが、６０万円／年に低減され、コンパクトで、低設備費、低変動費のバイオガスからをＣＯ２除去しＣＨ４を分離する方法および装置を提供することが出来る。 Regarding the cost of the above-mentioned conventional 15m 3 N / h CH 4 purification / separation recovery production equipment, PSA-CH4 of high pressure adsorption-atmospheric pressure regeneration is biogas compressor, two CO 2 adsorption towers, valves With 8 basic structures, the equipment cost is about 7 million yen, the basic unit of electricity is 1 kWh / m 3 N-O 2 , and the annual power consumption is 10 yen / kWh. 1,200,000 yen / year. On the other hand, if the method for separating CH 4 from the biogas of the present invention and the apparatus for separating CH 4 from the biogas, the PSA-CH4 for high pressure adsorption-regeneration at atmospheric pressure is used as a blower / vacuum pump. The equipment cost is reduced to about 4 million yen with a machine, 5 CO 2 adsorption towers and 4 auxiliary adsorption tower valves as basic structure, and the CH 4 recovery rate is achieved by recovering residual CH 4 by the auxiliary adsorption tower and supplying it to the pressurization process. Is increased from the conventional 80% to about 90%, so the power consumption is reduced to 0.5 kWh / m 3 N-CH 4 and the power consumption per year is 10 yen / kWh. The annual power cost is reduced to 600,000 yen / year, and it is possible to provide a method and apparatus for removing CO 2 and separating CH 4 from a compact, low equipment cost and low variable cost biogas.
本発明の第一の形態としては、水分、揮発性有機化合物（ＶＯＣ）、二酸化炭素（ＣＯ２）、硫化水素（Ｈ２Ｓ）、有機硫黄化合物、有機ケイ素化合物等を含有するメタン発酵槽からのＣＨ４含有湿りバイオガスからのコンパクトで高効率なＣＨ４の分離方法である。ここで、揮発性有機化合物とは、常温常圧で大気中に容易に揮発する有機化合物をさす。例えば、ホルムアルデヒド、ベンゼン、トルエン、キシレン、クレゾール、フェノール、ベンズアルデヒド、スチレン、クロロホルム、ジクロロメタン、ジクロロエタン、四塩化炭素、トリクロロエチレン、テトラクロロエチレン、ブロモホルム、クロロベンゼン、ジクロロベンゼン、アセトン、メチルエチルケトン、ジエチルケトン、アセトアルデヒド、プロピオンアルデヒド、アクロレイン、酢酸エチル、酢酸ブチル、酢酸ビニル、ジエチルエーテル、テトラヒドロフラン、ジオキサン、ピリジン、ピロール、ビニルピリジンなどである。有機ケイ素化合物とは、ケイ素を含有する有機化合物をさす。例えば、有機シロキサン、有機シラン、有機ケイ素ポリマー、シレンなどである。また、有機硫黄化合物とは、硫黄を含有する有機化合物をさし、例えば、チオール、スルホキシド、スルホン、チオケトン、スルホン酸エステル、スルホン酸アミド、チオエーテル、チオフェン、具体的にはメチルメルカプタンなどである。 As a first aspect of the present invention, from a methane fermenter containing water, volatile organic compounds (VOC), carbon dioxide (CO 2 ), hydrogen sulfide (H 2 S), organic sulfur compounds, organosilicon compounds, etc. This is a compact and highly efficient method for separating CH 4 from wet CH 4 -containing biogas. Here, the volatile organic compound refers to an organic compound that easily volatilizes in the atmosphere at normal temperature and pressure. For example, formaldehyde, benzene, toluene, xylene, cresol, phenol, benzaldehyde, styrene, chloroform, dichloromethane, dichloroethane, carbon tetrachloride, trichloroethylene, tetrachloroethylene, bromoform, chlorobenzene, dichlorobenzene, acetone, methyl ethyl ketone, diethyl ketone, acetaldehyde, propionaldehyde , Acrolein, ethyl acetate, butyl acetate, vinyl acetate, diethyl ether, tetrahydrofuran, dioxane, pyridine, pyrrole, vinylpyridine and the like. An organosilicon compound refers to an organic compound containing silicon. For example, organosiloxane, organosilane, organosilicon polymer, silene and the like. The organic sulfur compound refers to an organic compound containing sulfur, such as thiol, sulfoxide, sulfone, thioketone, sulfonic acid ester, sulfonic acid amide, thioether, thiophene, specifically methyl mercaptan.
さらに、本発明の他の実施形態においては、バイオガスからＣＨ４を分離するための装置に関する。 Furthermore, another embodiment of the invention relates to an apparatus for separating CH 4 from biogas.
当該装置は、例えば、図１に示されるような構成を有し、ＣＨ４製造量５０〜２５０リットルＮ／分、好ましくはＣＨ４製造量８５〜２００リットルＮ／分程度の装置とする。具体的には、
ＣＯ２吸着塔５から上流および下流の各々に二股に分岐している流路を有するＣＯ２吸着塔５を有し、
ＣＯ２吸着塔５から上流に二股に分岐している流路のうち一方にはバルブ４を介してさらに上流に二股に分岐している流路と連結し、
当該バルブ４を介してさらに上流に二股に分岐している流路のうち一方においてはバルブ１４を介して流路１６により外部と通じ、
当該バルブ４を介してさらに上流に二股に分岐している流路のうち上記とは別の流路の上流には、さらに上流にバルブ２を介してバイオガスを供給する流路１を有する圧力調整装置３があり、
ＣＯ２吸着塔から上流に二股に分岐している流路のうち上記とは別の流路１５はバルブ１３を介してバルブ２の下流で流路１と接続し、
ＣＯ２吸着塔５から下流に二股に分岐している流路うち一方にはバルブ１２を介して補助吸着塔６が接続され、
ＣＯ２吸着塔５から下流に二股に分岐している流路のうち上記とは別の流路にはバルブ８を介してＣＨ４を回収する容器９が接続され、さらに、容器９の下流には、ユーザーがメタンガスを回収しやすいように、バルブ１０を介して外部に通じるＣＨ４を分離するための流路１１が接続してもよく、
ここでＣＯ２吸着塔５には、上流から順に、Ｈ２Ｓ・有機硫黄選択型吸着剤５１、水分選択型吸着剤５２、ＶＯＣ・有機ケイ素選択型吸着剤５３およびＣＯ２選択型吸着剤７１、７２が充填されており、
さらに、好ましくは補助吸着塔６にはＣＯ２選択型吸着剤７３が充填されていればよい。
The apparatus has, for example, the configuration shown in FIG. 1, and is an apparatus having a CH 4 production amount of 50 to 250 liters N / min, and preferably a CH 4 production amount of 85 to 200 liters N / min. In particular,
A CO 2 adsorption tower 5 having a flow path bifurcated into upstream and downstream from the CO 2 adsorption tower 5;
One of the channels bifurcated upstream from the CO 2 adsorption tower 5 is connected to a channel bifurcated further upstream via the valve 4,
One of the flow paths branched bifurcated further upstream through the valve 4 communicates with the outside through the valve 14 through the flow path 16.
A pressure having a flow path 1 for supplying biogas via a valve 2 to the upstream of a flow path different from the above among the flow paths bifurcated upstream via the valve 4. There is an adjustment device 3,
Of the flow paths bifurcated upstream from the CO 2 adsorption tower, a flow path 15 different from the above is connected to the flow path 1 downstream of the valve 2 via the valve 13,
An auxiliary adsorption tower 6 is connected through a valve 12 to one of the channels bifurcated downstream from the CO 2 adsorption tower 5.
A vessel 9 for recovering CH 4 is connected to a channel different from the above among the channels bifurcated downstream from the CO 2 adsorption tower 5, and further downstream of the container 9. May be connected to a flow path 11 for separating CH 4 communicating to the outside through a valve 10 so that the user can easily collect methane gas,
Here, in the CO 2 adsorption tower 5, an H 2 S / organic sulfur selective adsorbent 51, a moisture selective adsorbent 52, a VOC / organosilicon selective adsorbent 53, and a CO 2 selective adsorbent 71 are arranged in this order from upstream. , 72 are filled,
Furthermore, it is preferable that the auxiliary adsorption tower 6 be filled with the CO 2 selective adsorbent 73.
さらに、ＣＯ２吸着塔５の容量としては、上記製造量を担保できる大きさであればよいが、例えば、１００〜１５０リットルであることが好ましい。また、補助吸着塔６についても、同様であり、例えば、１００〜１５０リットルであることが好ましい。 Furthermore, the capacity of the CO 2 adsorption tower 5 is not limited as long as the production amount can be secured, but is preferably 100 to 150 liters, for example. The same applies to the auxiliary adsorption tower 6, and for example, it is preferably 100 to 150 liters.
本発明の方法によれば、ＣＯ２吸着工程、残留ＣＨ４回収工程１、減圧再生工程、残留ＣＨ４回収工程２、昇圧工程を含み、これらを繰り返すバイオガスからＣＨ４を分離する方法である。本発明においては、当該５工程を上記の順で繰り返すことを特徴とする。本発明の方法においては、例えば、図１に示すような本発明の装置を使用すればよい。図１を使用して、ＰＳＡ−ＣＨ４の分離操作を構成する（吸着工程）→（残留ＣＨ４回収工程１）→（減圧真空再生工程）→（残留ＣＨ４回収工程２）→（昇圧工程）の各工程を以下に説明する。 According to the method of the present invention, the method includes a CO 2 adsorption step, a residual CH 4 recovery step 1, a decompression regeneration step, a residual CH 4 recovery step 2, and a pressure increase step, and these steps are repeated to separate CH 4 from biogas. . In the present invention, the five steps are repeated in the above order. In the method of the present invention, for example, an apparatus of the present invention as shown in FIG. 1 may be used. The separation operation of PSA-CH4 is configured by using FIG. 1 (adsorption process) → (residual CH 4 recovery process 1) → (reduced vacuum regeneration process) → (residual CH 4 recovery process 2) → (pressure increase process) Each process will be described below.
吸着工程
本工程においては、前方からＨ２Ｓ・有機硫黄選択型吸着剤５１、水分選択型吸着剤５２、揮発性有機化合物（以下、ＶＯＣとも示す）・有機ケイ素選択型吸着材５３の順序で吸着剤を充填され、さらに後方にＣＯ２選択型吸着剤７１、７２を充填されたＣＯ２吸着塔に、圧力調整装置３により大気圧より高い圧力としＣＨ４を主成分とする湿りバイオガスを供給して、ＶＯＣ、ＣＯ２、Ｈ２Ｓ、有機硫黄、有機ケイ素、水分を除去して塔後方からＣＨ４を回収する。
Adsorption process In this process, H 2 S, organic sulfur selective adsorbent 51, moisture selective adsorbent 52, volatile organic compound (hereinafter also referred to as VOC), and organic silicon selective adsorbent 53 are arranged in this order. A wet biogas containing CH 4 as a main component and having a pressure higher than the atmospheric pressure by the pressure adjusting device 3 is applied to the CO 2 adsorption tower filled with the adsorbent and further filled with the CO 2 selective adsorbents 71 and 72 at the rear. Then, VOC, CO 2 , H 2 S, organic sulfur, organic silicon, and water are removed to recover CH 4 from the rear of the tower.
ここで、本発明の方法および装置において使用されるＨ２Ｓ・有機硫黄選択型吸着剤５１としては、高シリカゼオライトを充填することが好ましい。ここで、高シリカゼオライトとは、シリカ／アルミナ比（モル／モル）が高い疎水性のゼオライトであり、本発明においては、シリカ／アルミナ比（モル／モル）が５以上のＨ２Ｓ・有機硫黄選択型吸着剤、または１０以上、例えば、シリカ／アルミナ比（モル／モル）が５０以上のものを使用すればよい。Ｈ２Ｓ・有機硫黄選択型吸着剤５１は、吸着剤の機能等にもよるが、ＣＯ２吸着塔５に４〜１５リットル、例えば、５〜８リットル充填することが好ましい。 Here, as the H 2 S • organic sulfur selective adsorbent 51 used in the method and apparatus of the present invention, high silica zeolite is preferably packed. Here, the high silica zeolite is a hydrophobic zeolite having a high silica / alumina ratio (mol / mol). In the present invention, the H 2 S.organic having a silica / alumina ratio (mol / mol) of 5 or more. A sulfur-selective adsorbent or one having 10 or more, for example, a silica / alumina ratio (mol / mol) of 50 or more may be used. The H 2 S / organic sulfur selective adsorbent 51 is preferably packed in 4 to 15 liters, for example, 5 to 8 liters, in the CO 2 adsorption tower 5 depending on the function of the adsorbent and the like.
ここで、本発明の方法および装置において使用される水分選択型吸着剤５２としては、Ｋ−Ａ型、Ｎａ−Ａ型、Ｎａ−Ｋ−Ａ型及びＣａ−Ａ型からなる群より選ばれる一種以上のゼオライトであることが好ましい。ここでＮａ−Ｋ−Ａ型は、Ｎａ−Ａ型ゼオライトのＮａの一部をＫに交換して熱処理することにより窓径を縮小させたものであり、この調製法は非特許文献１に記載されている。さらに、当該吸着剤においては、有機ケイ素化合物の加水分解生成物を気相又は液相で上記吸着剤結晶表面にシリカコートすることにより、水分選択性が強化される。本発明において水分選択型吸着剤として用いる結晶表面にシリカコートを施した吸着剤として、ハニカム形成されたものを用いれば、吸着剤吸着塔を通過する際の圧損が小さくなることから望ましい。ハニカムの調製法としては、アルミノシリケートの基材に当該ゼオライトとシリカゾル等の無機バインダーの混合スラリーに浸積して、これを乾燥するとゼオライトが担持される。浸積と乾燥を数回繰り返すと所定の担持量に達する。（嵩密度０．３以上、ゼオライト担持量０．１ｇ／ｍｌ以上）これを３５０℃以上、１時間焼成するとゼオライトの基材への固定と活性化が達成される。水分選択型吸着剤５２は、吸着剤の機能等にもよるが、ＣＯ２吸着塔５に４〜１５リットル、例えば、５〜８リットル充填することが好ましい。 Here, the moisture selective adsorbent 52 used in the method and apparatus of the present invention is a kind selected from the group consisting of KA type, Na-A type, Na-KA type and Ca-A type. The above zeolite is preferable. Here, the Na-KA type is obtained by reducing the window diameter by exchanging a part of Na of the Na-A type zeolite with K and performing heat treatment, and this preparation method is described in Non-Patent Document 1. Has been. Furthermore, in the adsorbent, moisture selectivity is enhanced by silica-coating the hydrolyzate of the organosilicon compound on the adsorbent crystal surface in the gas phase or liquid phase. In the present invention, it is desirable to use a honeycomb-formed adsorbent having a silica-coated crystal surface used as a moisture-selective adsorbent because pressure loss when passing through the adsorbent adsorption tower is reduced. As a method for preparing the honeycomb, the zeolite is supported by dipping in a mixed slurry of the zeolite and an inorganic binder such as silica sol on an aluminosilicate substrate and drying it. When the soaking and drying are repeated several times, a predetermined loading amount is reached. (Bulk density of 0.3 or more, zeolite loading of 0.1 g / ml or more) When this is calcined at 350 ° C. or more for 1 hour, fixation and activation of the zeolite to the base material are achieved. Although the moisture selective adsorbent 52 depends on the function of the adsorbent and the like, it is preferable to fill the CO 2 adsorption tower 5 with 4 to 15 liters, for example, 5 to 8 liters.
ここで、本発明の方法および装置において使用される揮発性有機化合物・有機ケイ素選択型吸着材５３としては、シリカライト、ＵＳＭ、β、ＵＳＹ、ＭＰＳからなる群より選ばれる一種以上であることが好ましい。揮発性有機化合物・有機ケイ素選択型吸着材５３は、吸着剤の機能等にもよるが、ＣＯ２吸着塔５に６〜２５リットル、例えば、８〜１５リットル充填することが好ましい。 Here, the volatile organic compound / organic silicon selective adsorbent 53 used in the method and apparatus of the present invention may be at least one selected from the group consisting of silicalite, USM, β, USY, MPS. preferable. The volatile organic compound / organosilicon selective adsorbent 53 is preferably packed in 6 to 25 liters, for example, 8 to 15 liters, in the CO 2 adsorption tower 5 depending on the function of the adsorbent and the like.
具体的には、例えば、圧力調整器としてのブロワー／真空ポンプ兼用回転機械３を有する図１に示される本発明の装置において、本発明の方法は実施される。バルブ２、バルブ４を開として、外部バイオガスを流路１からブロワー／真空ポンプ兼用回転機械３を通じてバイオガス流量２５０〜６５０リットルＮ／ｍｉｎ、好ましくは２００〜５００リットルＮ／ｍｉｎ、吸着圧力１２０〜１７５ｋＰａ−ａｂｓ、好ましくは吸着圧力１３５〜１６５ｋＰａ−ａｂｓで、ＣＯ２吸着塔５に、吸着時間５０〜７０秒、例えば、５５〜６５秒で供給する。ここで、ＣＯ２吸着塔５の吸着塔容量としては、１００〜１５０リットル、例えば、１１０〜１４０リットルであることが好ましい。 Specifically, for example, in the apparatus of the present invention shown in FIG. 1 having a blower / vacuum pump combined rotary machine 3 as a pressure regulator, the method of the present invention is carried out. With the valves 2 and 4 opened, the biogas flow rate is 250 to 650 liters N / min, preferably 200 to 500 liters N / min, and the adsorption pressure 120 through the blower / vacuum pump combined rotary machine 3 from the flow path 1. It is supplied to the CO 2 adsorption tower 5 at an adsorption time of 50 to 70 seconds, for example, 55 to 65 seconds, at ˜175 kPa-abs, preferably at an adsorption pressure of 135 to 165 kPa-abs. Here, the adsorption tower capacity of the CO 2 adsorption tower 5 is preferably 100 to 150 liters, for example, 110 to 140 liters.
本発明の方法および装置においては、バイオガス中の気体のうち硫黄含有成分を最初に除去するために、当該工程に使用されるＣＯ２吸着塔には、一番上流（前方）において、Ｈ２Ｓ・有機硫黄選択型吸着剤を充填する。硫黄成分は一般に反応性が高く、他の吸着剤と反応し、吸着剤の性能を低下させる可能性があるからである。さらに、Ｈ２Ｓ・有機硫黄選択型吸着剤の次には、ガス中の水分を除去するために水分選択型吸着剤、その次にはＶＯＣ・有機ケイ素選択型吸着材を充填されている。これにより、水分、ＶＯＣ・有機ケイ素化合物を吸着させ、後の吸着剤、特にＣＯ２選択型吸着剤の性能の低下を避けられるからである。さらに、この後方（下流）にはＣＯ２選択型吸着剤が充填されている。ここで、ＣＯ２選択型吸着剤については、２種類のＣＯ２選択型吸着剤が順に充填されていることが好ましい。さらに、ＣＯ２吸着塔に充填されるＣＯ２選択型吸着剤としては、Ｌｉイオン交換、Ｎａイオン交換、Ｃａイオン交換のＸ型ゼオライト、分子直径が４オングストローム以下のＣＯ２は吸着するがＣＨ４を吸着しないＮａ−Ｋ−Ａから成る群から選択させるゼオライトを１種または２種以上使用することが好ましい。特に好ましくは、シリカ／アルミナ比（モル／モル）が５より小さい、例えば、３より小さいＸ型ゼオライトを使用するとよい。吸着力が強くなるからである。２種類のＣＯ２選択型吸着剤の組み合わせとしては、いずれの組み合わせでも良いが、後方により高性能のＣＯ２選択型吸着剤を充填されていることが好ましい。これにより、段階的に効率よくＣＯ２を吸着させることができるからである。例えば、より前方にシリカ／アルミナ比（モル／モル）が４より小さいＬｉイオン交換のＸ型ゼオライトが充填され、分子直径が４オングストローム以下のＣＯ２は吸着するがＣＨ４を吸着しないＮａ−Ｋ−Ａ吸着剤が後方に充填されていることが好ましい。また、２種類のＣＯ２選択型吸着剤を混合して充填されていてもよい。ＣＯ２選択型吸着剤は、ＣＯ２吸着塔５の容積に対して、６０〜９０％程度充填することが好ましい。さらに、ＣＯ２選択型吸着剤は、ＣＯ２吸着塔５に合計で６０〜１２０リットル、例えば、９０〜１１０リットル充填することが好ましい。例えば、より前方にシリカ／アルミナ比（モル／モル）が４より小さいＬｉイオン交換のＸ型ゼオライトが４０〜６０リットル充填され、分子直径が４オングストローム以下のＣＯ２は吸着するがＣＨ４を吸着しないＮａ−Ｋ−Ａ吸着剤が後方に４０〜６０リットル充填されている形態が好ましい。 In the method and apparatus of the present invention, in order to first remove sulfur-containing components from the gas in the biogas, the CO 2 adsorption tower used in the process has H 2 at the most upstream (front). S. Organic sulfur selective adsorbent is filled. This is because the sulfur component is generally highly reactive and may react with other adsorbents, possibly reducing the performance of the adsorbents. Further, the H 2 S / organic sulfur selective adsorbent is filled with a water selective adsorbent to remove moisture in the gas, and then a VOC / organic silicon selective adsorbent. This is because moisture and a VOC / organosilicon compound can be adsorbed, and deterioration of the performance of the subsequent adsorbent, particularly the CO 2 selective adsorbent can be avoided. Further, this rear (downstream) is filled with a CO 2 selective adsorbent. Here, the CO 2 selective adsorbent, it is preferable that two types of CO 2 selective adsorbent is filled in sequence. Further, as the CO 2 selective adsorbent packed in the CO 2 adsorption tower, Li ion exchange, Na ion exchange, Ca ion exchange X-type zeolite, CO 2 having a molecular diameter of 4 angstroms or less is adsorbed, but CH 4. It is preferable to use one or more types of zeolite selected from the group consisting of Na—K—A that does not adsorb. Particular preference is given to using zeolite X with a silica / alumina ratio (mol / mol) of less than 5, for example less than 3. This is because the adsorption power becomes stronger. Any combination of the two types of CO 2 selective adsorbents may be used, but it is preferable that a higher performance CO 2 selective adsorbent is filled in the rear. This is because CO 2 can be adsorbed efficiently step by step. For example, a Li ion-exchanged X-type zeolite having a silica / alumina ratio (mol / mol) smaller than 4 is filled in the front, and CO 2 having a molecular diameter of 4 angstroms or less is adsorbed but not CH 4. It is preferable that -A adsorbent is filled rearward. Two kinds of CO 2 selective adsorbents may be mixed and filled. The CO 2 selective type adsorbent is preferably filled with about 60 to 90% with respect to the volume of the CO 2 adsorption tower 5. Further, the CO 2 selective adsorbent is preferably packed in the CO 2 adsorption tower 5 in a total of 60 to 120 liters, for example, 90 to 110 liters. For example, 40-60 liters of Li ion-exchanged X-type zeolite having a silica / alumina ratio (mol / mol) smaller than 4 is packed in the front, and CO 2 having a molecular diameter of 4 angstroms or less is adsorbed but CH 4 is adsorbed. It is preferable that the Na-KA adsorbent not filled is filled in the back by 40 to 60 liters.
供給されたバイオガス中の水分、揮発性有機化合物（ＶＯＣ）、硫化水素（Ｈ２Ｓ）、有機硫黄化合物、有機ケイ素化合物が上記のように吸着剤で除去され、ＣＯ２がＣＯ２吸着塔に充填された２種類のＣＯ２吸着剤７１，７２で除去されると、ＣＯ２吸着塔５の後方からＣＨ４が、ＣＨ４濃度８７〜９３ｖｏｌ％程度で、未吸着のＣＯ２とともにバルブ８を介して製品ＣＨ４タンク９に供給されるとよい。さらに、バルブ１０、流路１１から流過させてもよい。 Moisture, volatile organic compound (VOC), hydrogen sulfide (H 2 S), organic sulfur compound, and organic silicon compound in the supplied biogas are removed by the adsorbent as described above, and CO 2 is a CO 2 adsorption tower. Once removed filled two CO 2 adsorbents 71 and 72, rearwardly from CH 4 of CO 2 adsorption column 5, at about CH 4 concentration 87～93Vol%, with CO 2 unadsorbed valve 8 It is good to be supplied to product CH 4 tank 9 via. Further, it may flow from the valve 10 and the flow path 11.
残留メタン回収工程１
吸着工程の進行に伴い、ＣＯ２吸着塔７１，７２のＣＯ２吸着量が増大して吸着効率が悪くなり、流過ＣＨ４濃度が低下する可能性がある。したがって流過ＣＨ４濃度が低下する直前に、残留メタン回収工程１に移行する。当該工程においては、圧縮機／真空ポンプ兼用回転機械３を停止して、バルブ２、バルブ４、バルブ８、バルブ１３を閉として、バルブ１２を開とする。これにより、ＣＯ２吸着塔５の後方に残留するＣＨ４は、バルブ１２を通じて補助吸着塔６に移行する。ここで、ＣＯ２吸着塔５の圧力は１２０〜１７５ｋＰａ−ａｂｓから６０〜９０ｋＰａ程度、例えば、８０ｋＰａ程度に低下し、一方、補助吸着塔６の圧力も同様に６０〜９０ｋＰａ程度、例えば、８０ｋＰａ程度となる。補助吸着塔６に充填されるＣＯ２吸着剤７３としては、ＣＨ４に比べてＣＯ２を選択的に吸着する、Ｌｉイオン交換、Ｎａイオン交換、Ｃａイオン交換のＸ型ゼオライト、分子直径が４オングストローム以下のＣＯ２は吸着するがＣＨ４を吸着しないＮａ−Ｋ−Ａ型ゼオライト（ＣＯ２選択型吸着剤）を１種または２種以上使用するのが好ましい。前述の吸着工程でのＣＨ４の回収率は６８〜７２％程度、例えば７０％超程度にとどまる場合があり、この場合、残る３０％のＣＨ４は吸着塔の死容積部およびＣＯ２吸着剤への共吸着ＣＨ４として残留しており、依然ＣＨ４の回収効率を上げる余地がある。そこで補助吸着塔６にＣＯ２吸着塔４後方から高圧気体が移動すると、ＣＯ２吸着塔５に残留するＣＨ４は更に１８〜２２％程度回収され、全回収率が上昇する。
Residual methane recovery process 1
As the adsorption process proceeds, the CO 2 adsorption amount of the CO 2 adsorption towers 71 and 72 increases, the adsorption efficiency becomes worse, and the flow-through CH 4 concentration may decrease. Therefore, the process proceeds to the residual methane recovery step 1 immediately before the flow-through CH 4 concentration decreases. In this process, the compressor / vacuum pump combined rotary machine 3 is stopped, the valve 2, the valve 4, the valve 8, and the valve 13 are closed, and the valve 12 is opened. Thereby, CH 4 remaining behind the CO 2 adsorption tower 5 moves to the auxiliary adsorption tower 6 through the valve 12. Here, the pressure of the CO 2 adsorption tower 5 is reduced from 120 to 175 kPa-abs to about 60 to 90 kPa, for example, about 80 kPa, while the pressure of the auxiliary adsorption tower 6 is similarly about 60 to 90 kPa, for example, about 80 kPa. It becomes. The CO 2 adsorbent 73 packed in the auxiliary adsorption tower 6 is an X-type zeolite of Li ion exchange, Na ion exchange, Ca ion exchange, which selectively adsorbs CO 2 compared to CH 4, and has a molecular diameter of 4 It is preferable to use one or more kinds of Na—KA type zeolite (CO 2 selective adsorbent) that adsorbs CO 2 below angstrom but does not adsorb CH 4 . The recovery rate of CH 4 in the aforementioned adsorption process may be about 68 to 72%, for example, about 70% or more. In this case, the remaining 30% of CH 4 is the dead volume of the adsorption tower and the CO 2 adsorbent. It remains as co-adsorbed CH 4 and still has room to increase the recovery efficiency of CH 4 . Therefore, when high-pressure gas moves from the back of the CO 2 adsorption tower 4 to the auxiliary adsorption tower 6, about 18 to 22% of CH 4 remaining in the CO 2 adsorption tower 5 is further recovered, and the total recovery rate is increased.
なお補助吸着塔６にＣＯ２吸着剤を充填しない場合であっても、当該工程を経ることにより、メタンガスが補助吸着塔６に滞留することになり、メタンガスの回収率は上昇する。さらに、ここで補助吸着塔６にＣＯ２吸着剤を充填することが好ましく、補助吸着塔に充填ＣＯ２吸着剤７３へのＣＯ２吸着がＣＨ４吸着よりも選択的なため、補助吸着塔６充填ＣＯ２吸着剤７３にはＣＯ２が選択的に吸着され、死容積部のＣＨ４濃度は上昇する。これは、後述する昇圧工程での塔後方への高濃度ＣＨ４の供給のために非常に重要である。残留ＣＨ４回収工程１は、５秒〜１５秒、好ましくは８〜１２秒程度で完了する。補助吸着塔６の容量としては、ＣＯ２吸着塔５と同程度でよく、１００〜１５０リットル、例えば、１１０〜１４０リットルであることが好ましい。この中に補助吸着塔に充填されるＣＯ２吸着剤７３の容量としては、ＣＯ２吸着塔５中に充填されるＣＯ２吸着剤の量と同程度でよい。すなわち、ＣＯ２選択型吸着剤は、補助吸着塔６に６０〜１２０リットル、例えば、９０〜１１０リットル充填することが好ましい。ＣＯ２吸着塔５の後方に残留するＣＨ４を効率良く吸着させ補助吸着塔中に保持するためである。 Even when the auxiliary adsorbing tower 6 is not filled with the CO 2 adsorbent, methane gas stays in the auxiliary adsorbing tower 6 through this process, and the methane gas recovery rate increases. Furthermore, since here aid in the adsorption tower 6 is preferable to fill the CO 2 adsorbent, CO 2 adsorption to fill CO 2 adsorbent 73 in the auxiliary adsorption column is more selective than CH 4 adsorption, the auxiliary adsorption tower 6 CO 2 is selectively adsorbed on the packed CO 2 adsorbent 73, and the CH 4 concentration in the dead volume increases. This is very important for the supply of high-concentration CH 4 to the rear of the tower in the pressurization step described later. Residual CH 4 recovery step 1 is completed in about 5 to 15 seconds, preferably about 8 to 12 seconds. The capacity of the auxiliary adsorption tower 6 may be the same as that of the CO 2 adsorption tower 5, and is preferably 100 to 150 liters, for example, 110 to 140 liters. The capacity of the CO 2 adsorbent 73 filled in the auxiliary adsorption tower may be approximately the same as the amount of the CO 2 adsorbent filled in the CO 2 adsorption tower 5. That is, it is preferable to fill the auxiliary adsorption tower 6 with 60 to 120 liters, for example, 90 to 110 liters, of the CO 2 selective adsorbent. This is because CH 4 remaining behind the CO 2 adsorption tower 5 is efficiently adsorbed and held in the auxiliary adsorption tower.
減圧再生工程
残留ＣＨ４回収工程でＣＯ２吸着塔５の圧力は、８０ｋＰａ−ａｂｓ程度に低下する。さらに、減圧再生工程においては、バルブ２、バルブ４、バルブ８、バルブ１２を閉とし、圧縮機／真空ポンプ兼用回転機械３を再度稼働させ、さらに減圧させた。これにより、補助吸着塔に高濃度のＣＨ４を滞留させる。さらに、バルブ１３、バルブ１４を開とする。これにより、ＣＯ２吸着塔５充填ＣＯ２吸着剤７１，７２から吸着ＣＯ２が離脱し、更に向流に流過するＣＯ２により、ＶＯＣ・有機ケイ素吸着剤５３からＶＯＣおよび有機ケイ素が離脱し、水分吸着剤５２から水分が離脱し、Ｈ２Ｓ・有機硫黄吸着剤５１からＨ２Ｓおよび有機硫黄が離脱し、これらを流路１６から排出させる。ＣＯ２吸着塔５に充填されたＣＯ２吸着剤７１，７２、ＶＯＣ・有機ケイ素吸着剤５３、水分吸着剤５２、Ｈ２Ｓ・有機ケイ素吸着剤５１は再生され、再び、ＶＯＣ、ＣＯ２、Ｈ２Ｓ、有機硫黄、有機ケイ素、水分を吸着できるようになる。ここでＣＯ２吸着塔５の圧力は８〜１２ｋＰａ−ａｂｓ程度、例えば、１０ｋＰａ−ａｂｓ（真空条件）に低下する。減圧再生工程は、５０〜７０秒、例えば、５５〜６５秒、６０秒程度で完了させるとよい。
In the decompression regeneration step residual CH4 recovery step, the pressure of the CO 2 adsorption tower 5 is reduced to about 80 kPa-abs. Further, in the decompression regeneration process, the valve 2, the valve 4, the valve 8, and the valve 12 were closed, and the compressor / vacuum pump combined rotary machine 3 was operated again to further reduce the pressure. Thereby, high concentration CH 4 is retained in the auxiliary adsorption tower. Further, the valves 13 and 14 are opened. As a result, the adsorbed CO 2 is desorbed from the CO 2 adsorbing tower 5 packed CO 2 adsorbents 71 and 72, and VOC and organosilicon are desorbed from the VOC / organosilicon adsorbent 53 by the CO 2 flowing countercurrently. , moisture is separated from the water absorbent 52, H 2 S and organic sulfur are extracted from the H 2 S · organosulfur adsorbent 51, is discharged them from the flow channel 16. CO 2 adsorbents 71 and 72 filled in the CO 2 adsorption column 5, VOC · organosilicon adsorbent 53, the moisture adsorbent 52, H 2 S · organosilicon adsorbent 51 is regenerated again, VOC, CO 2, It becomes possible to adsorb H 2 S, organic sulfur, organic silicon, and moisture. Here, the pressure of the CO 2 adsorption tower 5 is reduced to about 8 to 12 kPa-abs, for example, 10 kPa-abs (vacuum condition). The decompression regeneration step may be completed in 50 to 70 seconds, for example, about 55 to 65 seconds and about 60 seconds.
残留メタン回収工程２
当該工程においては、圧縮機／真空ポンプ兼用回転機械３を停止して、バルブ２、バルブ４、バルブ８、バルブ１３を閉として、バルブ１２を開とする。これにより、１０ｋＰａ−ａｂｓ（真空条件）よりも高い圧力にある補助吸着塔６に滞留しているメタンガスがＣＯ２吸着塔後方に高濃度のＣＨ４として供給される。さらに、補助吸着塔６にＣＯ２吸着剤を充填している場合、補助吸着塔６から先ず死容積部の比較的ＣＨ４濃度の高い気体が、ＣＯ２吸着塔５後方からＣＯ２吸着塔５に供給され、その後補助吸着塔充填ＣＯ２吸着剤７３から吸着されたＣＨ４および共吸着ＣＯ２が離脱して供給ＣＨ４濃度が上昇するため、ＣＯ２吸着塔後方にはさらに高濃度のＣＨ４が供給される。いずれの場合にしろ、このため、ＣＯ２吸着塔５のＣＨ４濃度分布は、吸着工程開始時に塔前方のＣＨ４濃度は低く、塔後方のＣＨ４濃度分布が高くなり、効率的なバイオガスからのＣＨ４とＣＯ２分離の可能な状態となっている。残留ＣＨ４回収工程２は、５秒〜１５秒、好ましくは８〜１２秒程度で完了する。
Residual methane recovery process 2
In this process, the compressor / vacuum pump combined rotary machine 3 is stopped, the valve 2, the valve 4, the valve 8, and the valve 13 are closed, and the valve 12 is opened. As a result, methane gas staying in the auxiliary adsorption tower 6 at a pressure higher than 10 kPa-abs (vacuum condition) is supplied as high-concentration CH 4 behind the CO 2 adsorption tower. Furthermore, when filling the auxiliary adsorption column 6 CO 2 sorbent, relatively CH 4 high concentration gas first dead volume from the auxiliary adsorption column 6, CO 2 adsorption tower 5 rearwardly from CO 2 adsorption column 5 Since the CH 4 and co-adsorbed CO 2 adsorbed from the auxiliary adsorption tower packed CO 2 adsorbent 73 are then released and the supply CH 4 concentration rises, a higher concentration of CH 4 is provided behind the CO 2 adsorption tower. 4 is supplied. In any case, for this reason, the CH 4 concentration distribution of the CO 2 adsorption tower 5 has a low CH 4 concentration at the front of the tower at the start of the adsorption process, and a high CH 4 concentration distribution at the rear of the tower, which is an efficient biogas. From which CH 4 and CO 2 can be separated. Residual CH 4 recovery step 2 is completed in about 5 to 15 seconds, preferably about 8 to 12 seconds.
昇圧工程
ここで、さらに、バルブ２およびバルブ４を開とし、バルブ１２を閉とし、圧縮機３を作動させ、圧力を高める。すなわち、補助吸着塔６への流れを遮断し、外部バイオガスを流路１からバルブを２、バルブ４を開としてブロワー／真空ポンプ兼用回転機械３を通じてバイオガス流量２５０〜６５０リットルＮ／ｍｉｎ、好ましくは２００〜５００リットルＮ／ｍｉｎ、ＣＯ２吸着塔５における吸着圧力１２０〜１７５ｋＰａ−ａｂｓ、好ましくは吸着圧力１３５〜１６５ｋＰａ−ａｂｓとし、吸着工程の前準備を行う。当該昇圧工程は、２〜６秒、好ましくは３〜５秒程度で完了すればよい。昇圧工程で、残留ＣＨ４回収工程で補助吸着塔６に回収された残留ＣＨ４がＣＯ２吸着塔後方には高濃度で供給されているため、後の吸着工程において効率的にＣＨ４の回収を行うことができる。本発明においては、当該昇圧工程を終了後に、バルブ８を開として吸着工程に戻り、（吸着工程）→（残留ＣＨ４回収工程１）→（減圧真空再生工程）→（残留ＣＨ４回収工程２）→（昇圧工程）を繰り返すことでＣＨ４含有湿りバイオガスからメタンを分離することができる。
Here boosting step, further, the valve 2 and the valve 4 is opened, the valve 12 is closed to actuate the compressor 3, increasing the pressure. That is, the flow to the auxiliary adsorption tower 6 is shut off, and the external biogas is supplied from the flow path 1 to the valve 2 and the valve 4 is opened, and the biogas flow rate is 250 to 650 liters N / min through the blower / vacuum pump combined rotary machine 3. Preferably, the adsorption pressure is set to 200 to 500 liter N / min, the adsorption pressure in the CO 2 adsorption tower 5 is 120 to 175 kPa-abs, preferably the adsorption pressure is 135 to 165 kPa-abs, and preparation for the adsorption step is performed. The boosting step may be completed in 2 to 6 seconds, preferably about 3 to 5 seconds. In boosting step, the recovery of the residual CH 4 for the recovery step is recovered in the auxiliary adsorption column 6 residual CH 4 is the CO 2 adsorption column rearward is supplied at high concentrations, efficient in the adsorption step after CH 4 It can be performed. In the present invention, after completion of the pressure increasing process, the valve 8 is opened and the process returns to the adsorption process. (Adsorption process) → (Residual CH 4 recovery process 1) → (Reduced vacuum regeneration process) → (Residual CH 4 recovery process 2) ) → (Pressurization step) can be repeated to separate methane from the CH 4 -containing wet biogas.
以下の表１に本発明の１塔式圧力スイング法（以下ＰＳＡ−ＣＨ４）の方法を構成する、（吸着工程）→（残留ＣＨ４回収工程１）→（減圧再生工程）→（残留ＣＨ４回収工程２）→（昇圧工程）のバルブの開閉、圧縮機／真空ポンプ兼用回転機械の運転・停止、各工程の所要時間の例を示す。 Table 1 below constitutes the method of the one-column pressure swing method (hereinafter referred to as PSA-CH 4 ) of the present invention, (adsorption process) → (residual CH 4 recovery process 1) → (reduced pressure regeneration process) → (residual CH 4 Recovery process 2) → (Pressurization process) Valve opening / closing, compressor / vacuum pump combined rotary machine operation / stop, and examples of required time for each process.
以下実施例により本発明をさらに具体的に説明する。 Hereinafter, the present invention will be described more specifically with reference to examples.
実施例１
本実施例の１塔式ＰＳＡ−ＣＨ４製造装置の仕様を表２に示す。
Example 1
Table 2 shows the specifications of the single-column PSA-CH4 production apparatus of this example.
本装置は、ＣＨ４製造量８５〜２００リットルＮ／分（５−１０ｍ３Ｎ／ｈ）を目標として製作したもので、ＣＯ２吸着塔５は内径が４０ｃｍ、高さ１００ｃｍであり、当該ＣＯ２吸着塔５には、表２に示される各種吸着剤が充填されており、補助吸着塔６には、補助吸着塔充填ＣＯ２吸着剤７３が７０ｋｇ（１００リットル）充填されている。 This apparatus was manufactured with a target of CH 4 production of 85 to 200 liters N / min (5-10 m 3 N / h). The CO 2 adsorption tower 5 has an inner diameter of 40 cm and a height of 100 cm. The two adsorption towers 5 are filled with various adsorbents shown in Table 2, and the auxiliary adsorption tower 6 is filled with 70 kg (100 liters) of the auxiliary adsorption tower-filled CO 2 adsorbent 73.
実施例１および２、比較例１の操作条件を表３に示す。 The operating conditions of Examples 1 and 2 and Comparative Example 1 are shown in Table 3.
実施例１においては、吸着圧力１５０ｋＰａ−ａｂｓ、再生終了圧力１０ｋＰａ−ａｂｓ、補助吸着塔５３残留ＣＨ４回収工程１の終了圧力８０ｋＰａ−ａｂｓ、補助吸着塔５３昇圧終了圧力１５０ｋＰａ−ａｂｓ、１サイクル１４３秒、ＣＯ２吸着剤として、ＣＯ２吸着塔５に、Ｌｉイオン交換Ｘ型ゼオライトが下流とし、５０リットルのＬｉイオン交換Ｘ型ゼオライトと５０リットルのＮａ−Ｋ−Ａを１：１で２層充填し、補助吸着塔６には１００リットルのＬｉイオン交換Ｘ型ゼオライトを充填している。外部バイオガスを流路１からバルブ２、バルブ４を開としてブロワー／真空ポンプ兼用回転機械３を通じてバイオガス流量３３３リットルＮ／ｍｉｎ、吸着圧力１５０ｋＰａ−ａｂｓで、吸着塔容量５０リットルのＣＯ２吸着塔５に、吸着時間６０秒で供給した（吸着工程）。ＣＯ２吸着塔５には、予め、前方に前処理用吸着材５としてまずＨ２Ｓ・有機硫黄吸着剤５１として高シリカゼオライト（シリカ／アルミナ比（モル／モル＝７０））を６．２５リットル充填し、次いで水分吸着剤５２として比表面積７００ｍ２／ｇ以上のシリカゲルがウオッシュコートされハニカム形成されたＮａ−Ｋ−Ａ型ゼオライトを６．２５リットル、最後方部に有機ケイ素（シロキサン）吸着剤５３であるＵＳＹを１２．５リットル多層に充填し、後方にはＣＯ２選択型吸着剤７１として、１．２ｍｍφのＬｉイオン交換Ｘ型ゼオライト７１（ＳｉＯ２／Ａｌ２Ｏ３比２．５）を５０リットル充填し、最後方部にはＣＯ２選択型吸着剤としてＮａ−Ｋ−Ａ型ゼオライト７２を５０リットル充填した。 In Example 1, adsorption pressure 150 kPa-abs, regeneration end pressure 10 kPa-abs, auxiliary adsorption tower 53 residual CH4 recovery step 1 end pressure 80 kPa-abs, auxiliary adsorption tower 53 pressurization end pressure 150 kPa-abs, one cycle 143 seconds As a CO 2 adsorbent, the CO 2 adsorption tower 5 is filled with Li ion-exchanged X-type zeolite downstream, and 50 liters of Li ion-exchanged X-type zeolite and 50 liters of Na—K—A are packed in two layers at a ratio of 1: 1. The auxiliary adsorption tower 6 is filled with 100 liters of Li ion-exchanged X-type zeolite. The external biogas is opened from the flow path 1 through the valve 2 and the valve 4 and through the blower / vacuum pump combined rotary machine 3 with a biogas flow rate of 333 liter N / min, an adsorption pressure of 150 kPa-abs and an adsorption tower capacity of 50 liters of CO 2 The tower 5 was supplied with an adsorption time of 60 seconds (adsorption process). In the CO 2 adsorption tower 5, a high silica zeolite (silica / alumina ratio (mole / mole = 70)) is first used as the H 2 S / organic sulfur adsorbent 51 as the pretreatment adsorbent 5 in advance 6.25. Next, 6.25 liters of Na-KA-type zeolite formed by washing with silica-coated silica gel having a specific surface area of 700 m 2 / g or more as moisture adsorbent 52, adsorbing organosilicon (siloxane) at the end USY which is the agent 53 is packed in 12.5 liter multilayer, and as the CO 2 selective adsorbent 71 on the back, 1.2 mmφ Li ion exchange X-type zeolite 71 (SiO 2 / Al 2 O 3 ratio 2.5 ) And 50 liters of Na—KA type zeolite 72 as a CO 2 selective adsorbent was filled in the rearmost part.
吸着工程の進行に伴い、ＣＯ２選択型吸着剤７１，７２のＣＯ２吸着量が増大して流過ＣＨ４濃度が低下する。流過ＣＨ４濃度が低下する直前に（６０秒の吸着工程の後）、圧縮機／真空ポンプ兼用回転機械３を停止して、バルブ２，バルブ４、バルブ８を閉として、バルブ１２を開とし、残留メタン回収工程１に移行し、ＣＯ２吸着塔５の後方に残留するＣＨ４は、バルブ１２を通じて補助吸着塔６に移行させた。補助吸着塔６の容量としては、１２５リットルであり、この中に補助吸着塔充填ＣＯ２吸着剤７３が１００リットル充填されている。ＣＯ２吸着塔５の圧力は１５０ｋＰａ−ａｂｓから８０ｋＰａに低下し、補助吸着塔６の圧力は８０ｋＰａ−ａｂｓとなった。当該残留メタン回収工程は、１０秒で完了した。 As the adsorption process proceeds, the CO 2 adsorption amount of the CO 2 selective adsorbents 71 and 72 increases and the flow-through CH 4 concentration decreases. Immediately before the flow-through CH 4 concentration decreases (after the adsorption process for 60 seconds), the compressor / vacuum pump combined rotary machine 3 is stopped, the valves 2, 4 and 8 are closed, and the valve 12 is opened. The CH 4 remaining behind the CO 2 adsorption tower 5 was moved to the auxiliary adsorption tower 6 through the valve 12. The capacity of the auxiliary adsorption tower 6 is 125 liters, and 100 liters of the auxiliary adsorption tower-filled CO 2 adsorbent 73 is filled therein. The pressure of the CO 2 adsorption tower 5 decreased from 150 kPa-abs to 80 kPa, and the pressure of the auxiliary adsorption tower 6 became 80 kPa-abs. The residual methane recovery process was completed in 10 seconds.
続く減圧再生工程においては、残留メタン回収工程１で８０ｋＰａ−ａｂｓ程度に低下したＣＯ２吸着塔５の圧力を、圧縮機／真空ポンプ兼用回転機械３を稼働させてさらに減圧し、バルブ２、バルブ４、バルブ８、バルブ１２を閉として、バルブ１３、バルブ１４を開とした。ＣＯ２吸着塔５に充填したＣＯ２吸着剤７１、７２から吸着ＣＯ２が離脱し、更に向流に流過するＣＯ２により、有機ケイ素吸着剤５３から有機ケイ素が離脱し、水分吸着剤５２から水分が離脱し、Ｈ２Ｓ・有機硫黄吸着剤５１からＨ２Ｓ・有機硫黄吸着剤が離脱し、これらを流路１６から排出させた。当該工程は６０秒継続させた。 In the subsequent decompression regeneration step, the pressure of the CO 2 adsorption tower 5 that has decreased to about 80 kPa-abs in the residual methane recovery step 1 is further reduced by operating the compressor / vacuum pump combined rotary machine 3, and the valve 2, 4, valve 8 and valve 12 were closed, and valve 13 and valve 14 were opened. The adsorbed CO 2 is desorbed from the CO 2 adsorbents 71 and 72 packed in the CO 2 adsorption tower 5, and further, the organic silicon is desorbed from the organosilicon adsorbent 53 by the CO 2 flowing countercurrently, and the moisture adsorbent 52 The water was released from the H 2 S / organic sulfur adsorbent 51, and the H 2 S / organic sulfur adsorbent was released from the flow path 16. The process was continued for 60 seconds.
次に、圧縮機／真空ポンプ兼用回転機械３を停止して、バルブ２，バルブ４、バルブ８を閉として、バルブ１２を開とし、残留メタン回収工程２に移行した。当該工程は１０秒継続させた。これにより、塔後方のＣＨ４濃度分布が高い、効率的なバイオガスからのＣＨ４とＣＯ２分離の可能な状態とした。次に、バルブ２およびバルブ４を開とし、バルブ１２を閉とし、圧縮機３を作動させ、圧力を高め、昇圧工程に移行した。ＣＯ２吸着塔５の圧力を１５０ｋＰａ−ａｂｓ程度に上昇させた。当該昇圧工程は、３秒行った。その後、その後バルブ８を開とし、圧縮機／真空ポンプ兼用回転機械３を引き続き稼働させ、再度、吸着工程とし、バイオガスを再度供給し、上記サイクルを繰り返した。これにより、ＣＨ４製造量１７０リットルＮ／分（５−１０ｍ３Ｎ／ｈ）、ＣＨ４濃度９０ｖｏｌ％の性能が確認された。 Next, the compressor / vacuum pump combined rotary machine 3 was stopped, the valves 2, 4 and 8 were closed, the valve 12 was opened, and the process went to the residual methane recovery step 2. The process was continued for 10 seconds. As a result, the CH 4 concentration distribution at the rear of the tower was high, and the CH 4 and CO 2 could be separated from the biogas efficiently. Next, the valve 2 and the valve 4 were opened, the valve 12 was closed, the compressor 3 was operated, the pressure was increased, and the pressure increasing process was started. The pressure of the CO 2 adsorption tower 5 was increased to about 150 kPa-abs. The pressure increasing step was performed for 3 seconds. Thereafter, the valve 8 was opened, the compressor / vacuum pump combined rotary machine 3 was continuously operated, the adsorption process was performed again, biogas was supplied again, and the above cycle was repeated. This confirmed the performance of a CH 4 production amount of 170 liters N / min (5-10 m 3 N / h) and a CH 4 concentration of 90 vol%.
比較例１
補助吸着塔６がなく、吸着工程および減圧再生工程のみで行うことを除き、実施例１と同様にメタン分離に行った。
Comparative Example 1
The methane separation was performed in the same manner as in Example 1 except that the auxiliary adsorption tower 6 was not provided and only the adsorption step and the reduced pressure regeneration step were performed.
実施例２
補助吸着塔６に、ＣＯ２吸着剤を充填しないことを除き、実施例１と同様にメタン分離に行った。補助吸着塔６に、ＣＯ２吸着剤を充填していない場合であっても、補助吸着塔６を利用した残留メタン回収工程を利用することにより、表３に示すように、残留メタン回収工程および補助吸着塔を使用しない方法（比較例１）と比較して、回収率を上昇させることができることが確認された。
Example 2
Methane separation was performed in the same manner as in Example 1 except that the auxiliary adsorption tower 6 was not filled with a CO 2 adsorbent. Even when the auxiliary adsorption tower 6 is not filled with the CO 2 adsorbent, by using the residual methane recovery process using the auxiliary adsorption tower 6, as shown in Table 3, the residual methane recovery process and It was confirmed that the recovery rate can be increased as compared with the method not using the auxiliary adsorption tower (Comparative Example 1).
実施例３
ＣＯ２吸着塔５にＬｉイオン交換Ｘ型ゼオライトとＮａ−Ｋ−Ａを１：１で２層充填する代わりに、Ｎａイオン交換Ｘ型ゼオライトとＮａ−Ｋ−Ａを１：１で２層充填したこと、およびバイオガス供給量を３６６リットルＮ／ｍｉｎとしたことを除き、実施例１と同様にメタン分離に行った。
Example 3
Instead of filling the CO 2 adsorption tower 5 with two layers of Li ion-exchanged X-type zeolite and Na-KA in 1: 1, two layers of Na ion-exchanged X-type zeolite and Na-KA are packed in 1: 1. The methane separation was performed in the same manner as in Example 1 except that the amount of the biogas was 366 liter N / min.
実施例４
ＣＯ２吸着塔５にＬｉイオン交換Ｘ型ゼオライトとＮａ−Ｋ−Ａを１：１で２層充填する代わりに、Ｃａイオン交換Ｘ型ゼオライトとＮａ−Ｋ−Ａを１：１で２層充填したこと、およびバイオガス供給量を３５０リットルＮ／ｍｉｎとしたことを除き、実施例１と同様にメタン分離に行った。
Example 4
Instead of filling the CO 2 adsorption tower 5 with two layers of Li ion-exchanged X-type zeolite and Na-KA in 1: 1, two layers of Ca ion-exchanged X-type zeolite and Na-KA are packed in 1: 1. The methane separation was performed in the same manner as in Example 1 except that the biogas supply amount was 350 liters N / min.
実施例５
ＣＯ２吸着塔５にＬｉイオン交換Ｘ型ゼオライトとＮａ−Ｋ−Ａを１：１で２層充填する代わりに、Ｃａイオン交換Ａ型ゼオライトとＮａ−Ｋ−Ａを１：１で２層充填したこと、およびバイオガス供給量を２４０リットルＮ／ｍｉｎとしたことを除き、実施例１と同様にメタン分離に行った。
Example 5
Instead of filling the CO 2 adsorption tower 5 with two layers of Li ion-exchanged X-type zeolite and Na-KA in 1: 1, two layers of Ca ion-exchanged A-type zeolite and Na-KA are packed in 1: 1. This was performed for methane separation in the same manner as in Example 1 except that the biogas supply amount was 240 liter N / min.
実施例１および実施例３〜５の結果を比較した表を以下に示す。 A table comparing the results of Example 1 and Examples 3 to 5 is shown below.
Ｌｉイオン交換Ｘ型ゼオライト＋Ｎａ−Ｋ−Ａの２層充填が最もＣＨ４製造量が多く、最も効率良くＣＨ４を分離できることがわかった。Ｃａイオン交換Ｘ型ゼオライト、Ｎａイオン交換Ｘ型ゼオライトがこれに続く。 It was found that the two-layer packing of Li ion exchanged X-type zeolite + Na—KA has the largest amount of CH 4 production, and CH 4 can be separated most efficiently. This is followed by Ca ion exchange X-type zeolite and Na ion exchange X-type zeolite.
本発明は、１−２００ｍ３Ｎ／ｈ程度の分離能を有する中小容量のＣＨ４分離方法および装置に関し、ＣＨ４富化燃焼、環境装置、化学装置に使用する低コスト、コンパクトで高効率なバイオガスからの吸着法によるバイオガスからのＣＨ４の分離に利用できるものである。 The present invention relates to a small and medium volume CH 4 separation method and apparatus having a separation ability of about 1 to 200 m 3 N / h, and is low cost, compact and highly efficient for use in CH 4 enriched combustion, environmental equipment and chemical equipment. It can be used for separation of CH 4 from biogas by an adsorption method from biogas.
１、１１、１５、１６ 流路
３ 圧縮機／真空ポンプ兼用回転機械
２、４、８、１０、１２、１３、１４ バルブ
５ ＣＯ２吸着塔
５１ Ｈ２Ｓ・有機硫黄吸着剤
５２ 水分吸着剤
５３ ＶＯＣ・有機ケイ素吸着剤
７１、７２、７３ ＣＯ２吸着剤
９ 製品ＣＨ４タンク
６ 補助吸着塔
1, 11, 15, 16 Flow path 3 Compressor / vacuum pump combined rotary machine 2, 4, 8, 10, 12, 13, 14 Valve 5 CO 2 adsorption tower 51 H 2 S / organic sulfur adsorbent 52 Moisture adsorbent 53 VOC / Organic Silicon Adsorbent 71, 72, 73 CO 2 Adsorbent 9 Product CH 4 Tank 6 Auxiliary Adsorption Tower
Claims (7)
前方からＨ２Ｓ・有機硫黄選択型吸着剤、水分選択型吸着剤、揮発性有機化合物（以下、ＶＯＣと示す）・有機ケイ素選択型吸着材の順序で吸着剤が充填され、さらに後方にＣＯ２選択型吸着剤を充填されたＣＯ２吸着塔に、圧力調整装置により大気圧より高い圧力としＣＨ４を主成分とするバイオガスを供給して、ＶＯＣ、ＣＯ２、Ｈ２Ｓ、有機硫黄、有機ケイ素、水分を除去して塔後方からＣＨ４を回収して（ＣＯ２吸着工程）、
ＣＨ４濃度が低下する前に、塔後方に設置した補助吸着塔の前方とＣＯ２吸着塔の後方を連結して、塔後方に残留するＣＨ４を補助吸着塔に移行し（残留ＣＨ４回収工程１）、
補助吸着塔の前方とＣＯ２吸着塔の後方の連結を閉じ、真空ポンプ／ブロワー兼用回転機械で大気圧未満の圧力でＣＯ２吸着塔の塔前方から吸着したＶＯＣ、ＣＯ２、Ｈ２Ｓ、有機硫黄、有機ケイ素、水分を系外に排気した後（減圧再生工程）、
再度、補助吸着塔の前方とＣＯ２吸着塔の後方を連結して、大気圧のＣＯ２吸着塔の後方と補助吸着塔の前方を連結して回収したＣＨ４をＣＯ２吸着塔の後方へ移動させ、（残留ＣＨ４回収工程２）、
その後、ＣＨ４吸着塔の圧力を上昇させ（昇圧工程）、
ＣＨ４含有バイオガスを供給するＣＯ２吸着工程に戻ることを特長とする、バイオガスからＣＨ４を分離する方法。 A method of separating CH 4 from a biogas comprising a CO 2 adsorption step, a residual CH 4 recovery step, a decompression regeneration step, a residual CH 4 recovery step, and a pressure increase step, and repeating these steps,
The adsorbent is filled in the order of H 2 S / organic sulfur selective adsorbent, moisture selective adsorbent, volatile organic compound (hereinafter referred to as VOC) / organic silicon selective adsorbent from the front, and CO in the rear. A biogas mainly composed of CH 4 is supplied to a CO 2 adsorption tower packed with a two- selective adsorbent with a pressure higher than atmospheric pressure by a pressure regulator, and VOC, CO 2 , H 2 S, organic sulfur , Organic silicon, moisture is removed and CH 4 is recovered from the rear of the tower (CO 2 adsorption step),
Before the CH 4 concentration decreases, the front of the auxiliary adsorption tower installed behind the tower is connected to the rear of the CO 2 adsorption tower, and CH 4 remaining behind the tower is transferred to the auxiliary adsorption tower (residual CH 4 recovery). Step 1),
Close coupling of the rear of the front and CO 2 adsorption tower of the auxiliary adsorption tower, VOC adsorbed from the tower in front of CO 2 adsorption column at a pressure less than atmospheric pressure by a vacuum pump / blower combined rotary machine, CO 2, H 2 S, After exhausting organic sulfur, organic silicon, and moisture out of the system (reduced pressure regeneration process),
Again, by connecting the rear of the front and CO 2 adsorption tower of the auxiliary adsorption tower, CH 4 and CO 2 to the rear of the adsorption tower were collected by connecting the front of the rear auxiliary adsorption tower of the CO 2 adsorption column at atmospheric pressure (Residual CH 4 recovery step 2),
Thereafter, the pressure of the CH 4 adsorption tower is increased (pressure increase step),
A method for separating CH 4 from biogas, wherein the process returns to the CO 2 adsorption step for supplying CH 4 -containing biogas.
ＣＯ２吸着塔５から上流に二股に分岐している流路のうち一方にはバルブ４を介してさらに上流に二股に分岐している流路と連結し、
当該バルブ４を介してさらに上流に二股に分岐している流路のうち一方においてはバルブ１４を介して外部と通じ、
当該バルブ４を介してさらに上流に二股に分岐している流路のうち上記とは別の流路の上流には、さらに上流にバルブ２を介してバイオガスを供給する流路１を有する圧力調整装置３があり、
ＣＯ２吸着塔から上流に二股に分岐している流路のうち上記とは別の流路１５はバルブ１３を介してバルブ２の下流で流路１と接続し、
ＣＯ２吸着塔５から下流に二股に分岐している流路うち一方にはバルブ１２を介して補助吸着塔６が接続され、
ＣＯ２吸着塔５から下流に二股に分岐している流路のうち上記とは別の流路にはバルブ８を介してＣＨ４を回収する容器９が接続され、
ここでＣＯ２吸着塔５には、上流から順に、Ｈ２Ｓ・有機硫黄選択型吸着剤５１、水分選択型吸着剤５２、ＶＯＣ・有機ケイ素選択型吸着剤５３およびＣＯ２選択型吸着剤が充填されている、バイオガスからＣＨ４を分離するための装置。 A CO 2 adsorption tower 5 having a flow path bifurcated into upstream and downstream from the CO 2 adsorption tower 5;
One of the channels bifurcated upstream from the CO 2 adsorption tower 5 is connected to a channel bifurcated further upstream via the valve 4,
One of the flow paths branched into the upstream further through the valve 4 communicates with the outside through the valve 14.
A pressure having a flow path 1 for supplying biogas via a valve 2 to the upstream of a flow path different from the above among the flow paths bifurcated upstream via the valve 4. There is an adjustment device 3,
Of the flow paths bifurcated upstream from the CO 2 adsorption tower, a flow path 15 different from the above is connected to the flow path 1 downstream of the valve 2 via the valve 13,
An auxiliary adsorption tower 6 is connected through a valve 12 to one of the channels bifurcated downstream from the CO 2 adsorption tower 5.
A vessel 9 for collecting CH 4 is connected via a valve 8 to a channel different from the above among the channels bifurcated downstream from the CO 2 adsorption tower 5,
Here, in the CO 2 adsorption tower 5, H 2 S / organic sulfur selective adsorbent 51, moisture selective adsorbent 52, VOC / organosilicon selective adsorbent 53, and CO 2 selective adsorbent are sequentially arranged from the upstream. An apparatus for separating CH 4 from biogas that is being filled.
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| JP2020082015A (en) * | 2018-11-29 | 2020-06-04 | 株式会社コベルコ科研 | Adsorption tower and device for removing volatile organic compounds in gas |
| JP7166152B2 (en) | 2018-11-29 | 2022-11-07 | 株式会社コベルコ科研 | Adsorption tower and removal equipment for volatile organic compounds in gas |
| WO2023188520A1 (en) * | 2022-03-29 | 2023-10-05 | 三菱重工業株式会社 | Pre-treatment method, carbon dioxide collection method, and device for executing these methods |
| JP2023146402A (en) * | 2022-03-29 | 2023-10-12 | 三菱重工業株式会社 | Pretreatment methods, carbon dioxide recovery methods, and equipment for carrying out these methods |
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